For three days, geeks, online activists, and D.I.Y. filmmakers protested peacefully in Tahrir Square. For three nights, they slept in tents with laptops and cellphones charged by hacked street lights. On the fourth day, the lynch mob came.

Thousands of people supporting Egyptian President Hosni Mubarak laid siege to the central plaza, pressing themselves into the four streets that lead into Tahrir. They attacked the unarmed, crowds with clubs, knives, stones and Molotov cocktails. As I write this, reports put the death toll at three with around 1,500 injured.

"This was a real battle, a real Egyptian street fight, but we kept them back with stones and barricades and fire," computer security specialist Ahmad Gharbeia, 34, tells me over the phone. "They never reached our camp."

For the past six years, Gharbeia has been training Arab world activists, journalists and human rights lawyers to hide their Internet communications from prying eyes. "We use encryption techniques and PGP for email," he says. "We use proxies such as Tor that circumvent blocking. I was the Arabic editor of a tools set called Security in a Box. It's a tool kit of open and free software that helps advocates and human rights activists achieve security, privacy and anonymity."

The night before the siege, I interviewed him and his friends at their makeshift base-camp, a mesh of tents and small fires to keep warm while the group compiled a media archive of footage from the first days of the anti-Mubarak revolt. Over the weekend, around 100 people died when police shot tear gas and bullets at close range into protesters, and drove vehicles into crowds on a nearby bridge.

"It was very violent and brutal against peaceful people who just trying to cross the bridge… 17 people died right before my eyes," says Ahmad Abdalla, a 32-year-old filmmaker. "That has been motivating me to collect all the footage possible. We have three computers, Mac, Linux, PC, so we'll be able to handle everything. Cameras, mobile phones, anything."

Abdalla's latest project, Microphone, a film on Alexandria's underground music scene, was released the day the protests started. "The cinemas closed, so not many people have seen it," he said. "But I don't care, what's happening here is more important than any film."

For days, the crew could only collect photos and video, without distributing what they shot. Last Friday, the government shut down Internet access, and was only restored on Wednesday. In two days they have compiled more than 100 gigabytes of pictures and footage.

"The role of the Internet was critical at the beginning," Gharbeia says. "On the 25th, the movements of the protesting groups were arranged in real time through Twitter. Everyone knew were everyone else was walking and we could advise on the locations of blockades and skirmishes with police. It was real time navigation through the city, and that's why it was shut down."

While the Internet was cut, however, the groups made due by watching Al Jazeera. The protesters projected videos from the Qatar-based news channel last night – and passed along any news via landline or cell phone (when they were working).

Dissidents working under other oppressive regimes are used to navigating censorship. In Egypt, it's not a finely honed skill in Egypt, says Gharbeia's brother Amr (pictured, above). He works on Internet security with Amnesty International in London. Before this week, the Internet was almost completely open so there was no need to have those skills. The loss of such a basic tool enraged the tech crowd.

"Blocking the Internet was one of the biggest mistakes [the government] has made, plus cutting off mobile phones," said a former official in the ministry of communications who now works for a large computer company. "That made the people very angry and more aggressive."

Small pockets of Internet access, however, did exist at certain times. Egyptian authorities allowed small ISP Noor to operate until Monday morning. Le Monde reported that the government may have allowed Noor to continue because of its high-profile client list, including the Egyptian stock exchange, the Commercial International Bank of Egypt, the National Bank of Egypt and Egypt Air.

One of the protesters used Noor as well, so before Monday those at the protests would text or call the house with the connection, where half a dozen people uploaded the information to blogs and Facebook.

Mubarak's mob failed to break the Tahrir protesters resolve on Wednesday, and the Egyptian leader's incitement of violence will likely backfire against the 30-year regime. The crew, with their laptops in their tents, now surrounded by makeshift barricades, say they are not going anywhere.

"The running joke," Amr says, "is that the upcoming Arab League summit will need a lot of icebreakers because there will be so many new faces."